This clock simply couldn't be easier to use. All you have to do is insert an AA battery (sold separately) and press your corresponding time zone button, that's it! The clock receives radio communication from Fort Collins, Colorado, where the exact time signal is continuously broadcast throughout the United States. Time is precisely measured by the Atomic Clock of the US National Institute of Standards and Technology, Time and Frequency Division in Boulder, Colorado, where a team of atomic physicists continually measures time to an accuracy of ten billionths of a second per day. The clock recognizes Pacific Time (PT), Mountain Time (MT), Central Time (CT), Eastern Time (ET), and Fall and Spring daylight savings time adjustments if you are in one of the many contiguous states that change their clocks. It is suitable for indoor use as well as outdoor use in dry environments in a temperature range of 41&degF to 131&degF.

Please Note: For time zones outside of PT, MT, CT or ET you must manually set the time using the Manual Time set button on the back of the movement.

Hands On Research
At first the clock went to 4 o'clock and stopped. Upon reading the manual, I learned that every even hour is when the clock looks for a signal to set the clock to. Within a couple hours the clock read perfect time and everything was working great.Justin S. - Smarthome Product Testing